Cryogenic tank system

ABSTRACT

1,014,583. Pipe couplings. REYNOLDS METALS CO. Dec. 10, 1962 [Dec. 11, 1961; Nov. 9, 1962], No. 46556/62. Heading F2G. [Also in Division F4] In joining an aluminium pipe 47 to a steel pipe 39 having a short length of copper pipe 38 welded thereto, pipe lengths are tightly held in chucks 48, 49 which serve as electrodes to effect welding of the free end of the copper pipe 38 to the adjacent end of the aluminium pipe 47. The chucks are then slackened and cutting flanges 44 thereof used to remove outwardly upset metal. Inwardly upset metal is removed by a cutter 50 slidable within pipe 47 and bearing against an internal shoulder of the copper pipe 38.

March 15, 1966 c. R. DIXON 3,240,377

CRYOGENIC TANK SYSTEM Filed Nov. 9, 1962 2 Sheets-Sheet 1 FIG.I

F|G.3 FIG.2

W/ 38 W J FIG.4

cuAag f n DIXON BY a W 54, K

HIS ATTORNEYS March 15, 1966 c. R. DIXON 3,240,377

CRYOGENIC TANK SYSTEM Filed Nov. 9, 1962 2 Sheets-Sheet z FIG.8

WW r I INVENTOR CHARLES RALPH DIXON C L yg L5 5 FIG.9

HIS ATTORNEYS United Statm Patent 3,240,377 CRYOGENIC TANK-SYSTEMCharles Ralph Dixon, Henrico County, Va., assignor to Reynolds MetalsCompany, Richmond, Va., a corporation of Delaware Filed Nov. 9, 1962,Ser. No. 237,442 6 Claims. (Cl. 220-14) This application is acontinuation-in-part of the copending patent application, Serial No.158,392, filed December 11, 1961, and now abandoned.

This invention relates to improved cryogenic constructions and the likeas well as to improved parts and methods formaking such constructions orthe like.

It is well known that liquified cryogenic gases, such as liquid oxygen,nitrogen, helium and the like, have relatively low temperatures and mustbe stored in such a manner that the surrounding atmosphere will not tendto heat up and thereby boil the liquified cryogenic fluid.

For example, one such storage means comprises an inner metalliccontainer carrying the liquified cryogenic fluid and an outer metalliccontainer surrounding the inner container and spaced therefrom to definea chamber therebetween on which a vacuum is imposed and in which asuitable heat insulating means is disposed.

The liquified cryogenic fluid or the vapor therefrom is drawn as neededfrom the inner container by suitable piping passing from the exterior ofthe outer container throughthe containers into the interior of the innercontainer.

In such storage constructions, it has been found that such pipingreadily transmits heat from the outer container and surroundingatmosphere to the liquified cryogenie fluid to cause adverse boilingthereof.

However, according to the teachings of this invention, improved methodsand means are provided for substantially reducing such heat transferalong the piping of the cryogenic storage means.

In particular, improved transition joints or couplings "are provided forthe piping which greatly reduces the heat transfer along the pipesleading to the inner con- "tainer.

Therefore, it is an object of this invention to provide an improvedcryogenicconstruction or the like.

Another object of this invention is to provide an improved method formaking such a construction or the trating 'one cryogenic construction ofthis invention.

FIGURE 2 is an enlarged, fragmentary, cross-sectional view of theconstruction of FIGURE 1 and illustrates one embodiment of thetransition joint of this invention.

FIGURE 3 is a view similar to FIGURE 2 and illustrates anotherembodiment of this invention.

FIGURE 4 is an enlarged, fragmentary, cross-sectional view illustratingone of the steps of method of this invention for securing a length ofcopper pipe'to a length of steel pipe.

FIGURE 5 is a view similar to FIGURE 4 and illustrates another step ofthe method of this invention.

FIGURE6 is a fragmentary, cross-sectional view illustrating the copperpipe of FIGURE 4 secured to the steel pipe of FIGURE 4.

FIGURE 7 is a view similar to FIGURE 4 and illustratesanother step ofthe method of this invention for 3,240,377 Patented Mar. 15, 1966securing a length of aluminum pipe or the like to the pipe constructionillustrated in FIGURE 6.

FIGURE 8 is a view similar to FIGURE 7 and illustrates another step inthe method of this invention.

FIGURE 9 is a fragmentary cross-sectional view illustrating the lengthsof pipe secured together intheir completed form.

While the various features of this invention are hereinafter describedand illustrated as being particularly adaptable for use with liquifiedcryogenic fluids or the like, it is to be understood that the variousfeatures of this invention can be utilized singly or in any combinationthereof for other purposes as desired.

Therefore, this invention is not to be limited to only the embodimentsthereof illustrated in the drawings, because the drawings are merelyutilized to illustrate one of the wide variety of uses of thisinvention.

Referring now to FIGURE 1, an improved storage means of this inventionfor liquified cryogenic fluids or the like is generally indicated by thereference numeral 10 and comprises an inner metallic container 11 or thelike carrying a liquified cryogenic fluid 12 and being completelysurrounded by an outer metallic container 13 whereby a compartment 14 isdefined between the containers 11 and 13.

While the containers 11 and 13 can be formed of any suitable materialand in any suitable manner, the containers 11 and 13 of the embodimentillustrated in- FIG- URES 1 and 2 are formed of aluminum-containingmetallic material whereby the containers 11 and 13 each have asubstantially high coefficient of thermal conductivity.

In order to insulate the liquified cryogenic fluid 12 from the heat ofthe atmosphere surrounding the outer container 13, a vacuum is imposedin the compartment 14 by periodically inserting a pipe 15 into thecompartment 14, the pipe 15 being interconnected to a suitable suctionmeans which imposes a vacuum on the compartment 14.

In addition, suitable insulating means can be disposed in thecompartment 14. For example, an insulating material known as Perlite canbe utilized.

Various other pipes must pass from the exterior of the outer container13 into the interior of the inner container 11 for various purposes.

For example, should the cryogenic storage means 10 be utilizedforholding liquid oxygen or the like for hospital uses, it has been foundthat a conduit 16 must pass from the exterior of the container 13 to theinterior of the container 11 in the vapor region thereof so that oxygenin gaseous form can be drawn as needed from the storage means 10 and beconveyed to various parts of the hospital for well known uses thereof.

In addition, a conduit 17 may be provided and lead from the exterior ofthe container 13 to the interior of the container 11 below the liquidlevel thereof so that liquid oxygen can be drawn off as desired by theconduit 17 and be conveyed to various parts of the hospital for otherwell known uses.

Similarly, a conduit 18 can be p-rovided and leads from the exterior ofthe container 13 to the interior of the container 11 below the liquidlevel thereof so that liquid oxygen can be drawn off as needed toreplenish supplies on mobile units and the like, the conduit 18 havingsuitable heater means therein outboard of the container 13 to change theliquid oxygen to gas, or the mobile units themselves may contain suchheater means in a manner well known in the art.

Further, a suitable conduit 19 may be provided to interconnect theinterior of the container 11 with an exteriorly mounted pressureindicating device 20 to determine the pressure within the container 11.Similarly, a conduit 21 may be provided and lead from a suitableexteriorly mounted relief valve to the interior of the container 11 toprevent the pressure of the gas Within the container 11 from exceeding apredetermined amount.

It may be desired to provide a liquid level gauge 22 externally of thecontainer 13, the gauge 22 having opposed conduit legs 23 and 24respectively extending from the exterior of the container 13 into theinterior of the inner container 11.

Therefore, it can be seen that the various conduits 16, 17, 18, 19, 21,23 and 24 are readily adapted to transmit heat from the exterior of thecontainer 13 to the interior of the inner container 11 whereby suchtransferred heat tends to adversely boil the liquified cryogenic fluid12.

Therefore, such conduits cannot normally be made of aluminum-containingmetallic material or the like which has a relatively high coefficient ofthermal conducivity because of the resulting heat transfer providedthereby.

However, since the containers 11 and 13 are formed ofaluminum-containing metallic material, it has been found that it isrelatively difficult to secure pipes thereto when the pipes are formedof material other than aluminum-containing metallic material.

However, according to the teachings of this invention, aluminum pipesand the like can be utilized to form the cryogenic storage means becausetransition joints of this invention are disposed in the conduitsintermediate the containers 11 and 13 to substantially reduce heattransfer along the particular conduit leading to the interior of theinner container 11.

In particular, reference is made to FIGURE 2 wherein a length ofaluminum pipe 25 passes from the exterior of the outer container 13through the outer container 13 whereby an end 26 of the aluminum pipe 25is disposed within the compartment 14, the aluminum pipe 25 beingsuitably secured to the aluminum outer container 13 in a manner wellknown in the art.

Similarly, another length of aluminum pipe 27 extends from the interiorof the inner container 11 and through the same whereby an end 28 of thealuminum pipe 27 is disposed in the compartment 14, the aluminum pipe 27being secured to the inner aluminum container 11 in a manner well knownin the art.

The adjacent ends 26 and 28 of the aluminum pipes 25 and 27 are joinedor coupled together by a length of stainless steel pipe 29, the pipe 29being joined to the pipes 25 and 27 by the method of this invention inthe manner hereinafter described whereby the stainless steel pipe 29 hasa relatively low coefficient of thermal conducivity when compared withthe coeflicients of thermal conductivity of the aluminum pipes 25 and 27so that the tendency of the aluminum pipes 25 and 27 to conduct heatfrom the exterior of the container 13 to the interior of the container11 is greatly reduced by the length of stainless steel pipe 29.

Since it is relatively diflicult to secure aluminum to stainless steel,lengths of copper pipes 30 are utilized in a manner hereinafterdescribed to interconnect the ends 26 and 28 of the aluminum pipes 25and 27 to the opposed ends 31 and 32 of the stainless steel pipe 29.

When the outer container 13 is formed of steel or the like in the mannerillustrated in FIGURE 3, a steel pipe 33 can be utilized to interconnectthe exterior of the steel container 13 with the compartment 14 disposedbetween the containers 11 and 13 because it is relatively easy to securesuch steel pipes to the steel container 13.

However, since it is relatively diflicult to interconnect the steelpipes to the inner aluminum container 11, an aluminum pipe 34interconnects the interior of the inner container 11 with thecompartment 14 whereby adjacent ends 35 and 36 of the pipes 33 and 34can be joined together by a length of copper pipe 37 in a mannerhereinafter described so that a suitable transition joint is providedbetween the con ainers 11 and 13 to prevent the transfer of heatexternally of the container 13 from reaching the interior of thecontainer 11.

One method of this invention for forming the transition joint of FIGURE2 or FIGURE 3 is illustrated schematically in FIGURES 4-9 and will nowbe described.

As illustrated in FIGURE 4, a length of copper pipe 38 is secured to alength of stainless steel pipe 39 by a flash welding operation wherebythe pipes 38 and 39 are respectively tightly held in holding chucks 40and 41 which respectively receive an electrical current which tends toare between the adjacent ends 42 and 43 of the pipes 38 and 39 as thesame are brought closely adjacent to each other, the arcing suflicientlyheating the ends 42 and 43 of the pipes 38 and 39 so that the same willfuse or weld together when the pipes 38 and 39 are brought togetherunder pressure by the chucks 40 and 41 as illustrated in FIGURE 5.

As the ends 42 and 43 of the pipes 38 and 39 are being flash weldedtogether in the above manner, the heated metal at the ends 42 and 43thereof, is upset whereby the same flows inwardly and outwardly asillustrated in FIGURE 5 and must be subsequently removed to form asmooth weld.

One means for removing the upset metal at the exterior of the joinedpipes 38 and 39 to utilize the holding chucks 4i) and 41 themselves aspinch-off tools. For example, the holding chucks 40 and 41 have inwardlydirected beveled cutting flanges 44 which when brought together over thewelded joint pinches ofl the upset metal at the exterior of the joinedpipes 39 and 38 in the manner illustrated in FIGURE 5.

The upset metal at the interior of the joined pipes 38 and 39 can beremoved by subsequent internal reaming devices or the like whereby thejoined pipes 38 and 39 appear in the manner illustrated in FIGURE 6.

Thereafter, the copper pipe 38 is cut off to the desired length to formthe transition joint of this invention.

For example, it has been found that the length of the copper pipe 38 canbe approximately of an inch long to permit the same to be subsequentlysecured to an aluminum pipe.

After the copper pipe 38 and stainless steel pipe 3-9 have been joinedtogether in the manner previously described, the free end 45 of thecopper pipe 38 can be joined to an adjacent end 46 of an aluminum pipe47 in the manner illustrated in FIGURES 7 and 8.

Preferably, the aluminum pipe 47 has a larger intern-a1 diameter thanthe copper pipe 38 for a purpose hereinafter described.

The joined stainless steel pipe 39 and copper pipe 38 are tightly heldin a holding chuck 48 while the aluminum pipe 47 is tightly held in aholding chuck 49 whereby the holding chucks 48 and 49 are utilized toflash weld the ends 45 and 46 of the pipes 38 and 47 together insubstantially the same manner previously described.

However, a pinch-off device 50 is disposed in the aluminum pipe 47 andhas the cutting end 51thereof disposed in substantially the same planeas the cutting end '44 of the holding chuck 49.

As the electrical current is imposed on the holding chucks 48 and 49,and as the ends 45 and 46 of the pipes 38 and 47 are brought adjacenteach other, the electrical arcing between the pipes 38 and 47 heats theends 45 and 46 of the pipes 38 and 47 so that the same can be flashwelded together by moving the ends 45 and 46 of the pipes 38 and 47together under pressure whereby the pipes 38 and 47 are welded or fusedtogether.

As the ends 45 and 46 of the pipes 38 and 47 are being flash weldedtogether, the metal at the joined ends thereof is upset inwardly andoutwardly in the manner illustrated in FIGURE 8 whereby the upset metalcan be removed exteriorly of the welded joint by the pinch-off means 44of the holding chucks 48 and 49 in the manner previously described.

The metal that is upset inwardly of the pipes 38 and 47 can be removedby moving the pinch-off device 50 toward the end 45 of the copper pipe38 in the manner illustrated in FIGURE -8 whereby the end 45 of thecopper pipe 38 acts as an anvil for the cutting edge 51 of the pinch-offdevice 50.

Therefore, the resulting interconnected pipes 38, 39 and 47, when joinedtogether, appear as illustrated in FIGURE 9 whereby the same can beutilized to form the transition joint illustrated in FIGURE 3 for acryogenic storage means having an outer steel container and an inneraluminum container, the steel pipe '39 being joined to the steelcontainer '13 while the aluminum pipe 47 is joined to the aluminumcontainer 11 so that the copper pipe 38 and part of the pipes 39 and 47are disposed in the chamber 14 between theinner and outer containers 11and 13 as illustrated in FIGURE 3.

Should it be desired to form the joint structure illustrated in FIGURE2, wherein the inner and outer containers 11 and 13 are both formed fromaluminumcontaining metallic material, the other end of the stainlesssteel pipe 39 can be joined to another length of aluminum by anintermediate copper pipein substantially the same manner as illustratedin FIGURES 4-9 whereby the outboard aluminum pipes will be respectivelysecured to the inner and outer containers 1:1 and '13 while thestainless steel pipe 49 would be disposed in the compartment 14 toprovide the transition joint as illustrated in FIGURE 2.

In order to avoid brittleness in the joint between copper and aluminumit is preferable to maintain the eutectic zone bet-ween copper andaluminum very thin. It has been found that a copper-aluminum eutecticzone of 50 micro-inches or less avoids a brittle joint. Such a fineeutectic zone is achieved by using very fast upset speeds such as 12inches per second or faster.

Further, it has been found that when oxygen-free copper is utilized forthe transition joints of this invention improved flash Weldingcharacteristics are obtained when forming the eutectic zones between thedissimilar metals of the joint, such oxygen-free copper having alltraces of cuprous oxide removed therefrom where-by the oxygen-freecopper flash Welds more readily and withstands higher temperatures thancopper which has not been deoxidized. For example, such oxygen-freecopper has been found to perform more satisfactorily than electrolytictough pitch copper which contains 99.92% copper and a nominal oxygencontent of 0.04%, the oxygen range being from 0.01% to 0.07%.

When such oxygen-free copper was utilized with 304L stainless steel toform the transition joints of this invention, a more ductile eutecticzone was produced between the metal pipes whereby it can be seen thatthe use of oxygen-free copper with 304L stainless steel reduces thebrittleness of the euectic zone, therebetween to produce a strongertransition joint even though the eutectic zone is relatively thin.

The above oxygen-free copper is sometimes given the designation OFHC todenote oxygen-free as well as high conductive. The designation L of theabove stainless steel utilized means a low carbon content which has beenfound to reduce the brittleness of the eutectic zone.

Therefore, it can be seen that improved cryogenic constructions areprovided by this invention as well as an improved part and methods formaking the same or the like.

In addition, while the particular metals, aluminum, copper and steelhave been specified, it is to be understood that other metals can beutilized having different coefficients of thermal conductivity.

Further, while the terms aluminum and copper are utilized throughout, itis to be understood that such terms are intended to include such metalsin the pure state or any alloys thereof.

While the form of the invention now preferred has been disclosed asrequired by the statutes, other forms 6 may be used, all coming withinthe scope of the claims which follow.

"What is claimed is:

1. In a cryogenic system having means for conveying a cryogenicfiuid'havingalow boiling point, an aluminum container, a steel containersurrounding said aluminum container and being spaced therefrom to definea compartment therebetween, a length of aluminum pipe having one endthereof interconnected to said aluminum container and the otherendthereof-disposed in said compartment, a length of stainless steelpipe having one .end thereof interconnected to the exterior steelcontainer :and the other end thereof disposed insaid-compartmenhand alength of copper pipe having one end thereofflash welded to said otherend of said stainless steel pipe-and the other end thereof flash weldedtosaid otherlendof said aluminum pipe whereby said pipes provide-atransition joint between saidcontainers and iniwhich said-fluid can beconveyed in said system throughysaid interconnected pipes, and saidcopper .pipe being oxygen free to provide ductilexeutectic andtransition zones :between said copper .pipe and-said aluminum andstainlesssteel ,pipes.

2. In a cryogenic system having means for conveying a cryogenic fluidhaving a low boiling point,an aluminum container, a steel containersurrounding said aluminum container and being spaced therefrom to definea compartment therebetween, a length of aluminum pipe having one endthereof interconnected to the interior aluminum container and the otherend thereof disposed in said compartment, a length of stainless steelpipe having one end thereof interconnected to the exterior steelcontainer and the other end thereof disposed in said compartment, and alength of copper pipe having one end thereof flash welded to said otherend of said stainless steel pipe and the other end thereof flash weldedto said other end of said aluminum pipe whereby said pipes provide atransition joint between said containers and in which fluid can beconveyed in said system through said interconnected pipes, the flashwelded interconnection between said copper pipe and said aluminum pipehaving a thickness of 50 micro-inches or less whereby a ductileconnection is provided between said copper pipe and said aluminum pipe.

3. A cryogenic system having means for conveying a cryogenic fluidhaving a low boiling point as defined in claim 2 wherein said copperpipe is oxygen free.

4. In a cryogenic system having means for conveying a cryogenic fluidhaving a low boiling point, a first aluminum container, a secondaluminum container surrounding said first aluminum container and beingspaced therefrom to define a compartment therebetween, a first length ofaluminum pipe having one end thereof interconnected to said firstaluminum container and the other end thereof disposed in saidcompartment, a second length of aluminum pipe having one end thereofinterconnected to said second aluminum container and the other endthereof disposed within said compartment, a first length of copper pipehaving one end thereof flash welded to said other end of said firstaluminum pipe, a second length of copper pipe having one end thereofflash welded to said other end of said second aluminum pipe, and alength of stainless steel pipe having one end thereof flash welded tothe other end of said first copper pipe and the other end thereofsecured to the other end of said second copper pipe whereby said pipesprovide a transition joint between said containers and in which saidfluid can be conveyed in said system through said interconnected pipes,and said copper pipe being oxygen free to provide ductile eutectic andtransition zones between said copper pipe and said aluminum andstainless steel pipes.

5. In a cryogenic system having means for conveying a cryogenic fluidhaving a low boiling point, a first aluminum container, a secondaluminum container surrounding said first aluminum container and beingspaced therefrom to define a compartment therebetween, a first lengthaluminum pipe having one end thereof interconnected to said firstaluminum container and the other end thereof disposed in saidcompartment, a second length of aluminum pipe having one end thereofinterconnected to said second aluminum container and the other endthereof disposed in said compartment, a first length of copper pipehaving one end thereof flash welded to said other end of said firstaluminum pipe, a second length of copper pipe having one end thereofflash welded to the other end of said second aluminum pipe, and a lengthof stainless steel pipe having one end thereof flash welded to the otherend of said first copper pipe and the other end thereof flash welded tothe other end of said second copper pipe whereby said pipes provide atransition joint between said container and in which said fluid can beconveyed through said interconnected pipes, the flash weldedinterconnection between said copper pipe and said aluminum pipe having athickness of 50 micro-inches or less whereby a ductile connection isprovided between said copper pipe and said aluminum pipe.

6. A cryogenic system having means for conveying a cryogenic fluidhaving a low boiling point as defined in claim 5, wherein said first andsecond copper pipes are oxygen free.

References Cited by the Examiner UNITED STATES PATENTS Heylandt 220-15Moyer 219-97 Long 285-173 Grenell 285-176 Yeager 220-15 Harris et al.219-97 Bliss 220-9 Kaiser et a1. 219-97 Roovers 220-2.3 Stieglitz et al.219-97 Haumann et al. 220-15 Brown.

Morrison et al. 29-1962 Schlumberger.

Skinner 285-173 OTHER REFERENCES Handbook of Chemistry and Physics, 37thed., 1955,

THERON E. CONDON, Primary Examiner.

1. IN A CRYOGENIC SYSTEM HAVING MEANS FOR CONVEYING A CRYOGENIC FLUIDHAVING A LOW BOILING POINT, AN ALUMINUM CONTAINER, A STEEL CONTAINERSURROUNDING SAID ALUMINUM CONTAINER AND BEING SPACED THEREFROM TO DEFINEA COMPARTMENT THEREBETWEEN, A LENGTH OF ALUMINUM PIPE HAVING ONE ENDTHEREOF INTERCONNECTED TO SAID ALUMINUM CONTAINER AND THE OTHER ENDTHEREOF DISPOSED IN SAID COMPARTMENT, A LENGTH OF STAINLESS STEEL PIPEHAVING ONE END THEREOF INTERCONNECTED TO THE EXTERIOR STEEL CONTAINERAND THE OTHER END THEREOF DISPOSED IN SAID COMPARTMENT, AND A LENGTH OFCOPPER PIPE HAVING ONE END THEREOF FLASH WELDED TO SAID OTHER END OFSAID STAINLESS STEEL PIPE AND THE OTHER END THEREOF FLASH WELDED TO SAIDOTHER END OF SAID ALUMINUM PIPE WHEREBY SAID PIPES PROVIDE A TRANSITIONJOINT BETWEEN SAID CONTAINERS AND IN WHICH SAID FLUID CAN BE CONVEYED INSAID SYSTEM THROUGH SAID INTERCONNECTED PIPES, AND SAID COPPER PIPEBEING OXYGEN FREE TO PROVIDE DUCTILE EUTECTIC AND TRANSITION ZONESBETWEEN SAID COPPER PIPE AND SAID ALUMINUM AND STAINLESS STEEL PIPES.